Surgical apparatus and method for occluding or encircling a body passageway

ABSTRACT

A surgical apparatus and method for occluding or encircling a body passageway, e.g. for haemostasis, is described. The apparatus comprises generally a delivery system for offering a temperature-dependent shape memory material clip ( 3 ′) (e.g. of Nitinol and suitably of generally U-shape in the open (a) condition) onto the body passageway, allowing body heat to warm the clip whereby the clip closes to a closed (b) condition in which it occludes or encircles the body passageway. The apparatus is then withdrawn from the operating zone. The apparatus includes drive and control functions for moving a train of clips ( 3 ′) within a shaft ( 2 ′) of the apparatus towards a distal end port ( 6 ′), and preferably a temperature control system whereby the clips within the housing are maintained at a first temperature, substantially below body temperature.

FIELD OF THE INVENTION

The present invention relates to a surgical apparatus and method foroccluding or encircling a body passageway such as a blood vessel. Theinvention further relates to surgical clips suitable for use in such anapparatus and method. The word “surgical” herein includes human andveterinary surgery and the word “patient” herein includes human andanimal patients.

The word “occluding” herein includes complete or partial closure of abody passageway and the word “encircling” herein includes prevention ofexpansion of a body passageway without application of a constrictiveforce.

DESCRIPTION OF THE PRIOR ART

The surgical control of bleeding (haemostasis) by the closing of bloodvessels is one of the oldest and most fundamental principles of surgery.Modern techniques such as minimally-invasive surgery cannot be performedwithout effective haemostasis, but there are significant difficulties inthat the surgical instruments have to be controlled remotely from anoperating zone within a patient and the surgeon is typically viewing theoperating zone via an endoscope.

It is known to perform haemostasis during an endoscopicminimally-invasive surgical procedure by means of single sutures orligatures tied around individual blood vessels. It is also known to useclips in the form of V-shaped lengths of silver wire which are crampedacross the blood vessels. Sutures and ligatures are slow to apply asstitching or tying of individual threads is required, and the securementis technically difficult in endoscopic surgery. Silver clips are proneto dislodge.

Endoscopic staples are also Cloven for the occlusion of larger bodypassageways such as bronchi, the bile duct or bowel, but are too largefor use on individual small vessels. Sprung clips have been used toocclude aortic aneurysms in conventional open (non-endoscopic) surgery,but are too large for use in endoscopic minimally-invasive surgery.

Thus, for example, U.S. Pat. Nos. 5,02,6379, 5,217,473 and 5,226,908(Yoon), the disclosures of which are incorporated herein by reference,describe a ligating and occluding clip, useful in surgical sterilisationand other techniques, in which two straight legs are joined so that anelastic closing force closes the legs together across an anatomictubular structure. These U.S. patents also describe an applicator devicewhich releases the clip, legs splayed apart, onto the anatomic tubularstructure. The elastic closing force causes the legs to close onto, andclamp, the anatomic tubular structure.

U.S Pat. Nos 3,675,688 and 3,735,762 (Bryan et al), the disclosures ofwhich are incorporated herein by reference, describe a metal ligatingand occluding staple which is wrapped around an anatomic tubularstructure to occlude the same, as well as a cartridge applicator devicefrom which staples are dispensed and which includes parts which causeeach staple to be wrapped around the anatomic tubular structure andsubsequently sever the structure.

U.S. Pat. No. 4,950,258 (Kawai et al), the disclosure of which isincorporated herein by reference, describes a range of surgical articlesmoulded from shape memory plastics, the articles including cerebralaneurysm clips (FIGS. 7 and 8a-8 d) and a haemostatic clip (FIGS. 12aand 12 b) which generally have two straight legs joined so that theshape memory effect causes a closing force to be exerted to close thelegs together from a splayed apart condition (in which an anatomictubular structure can be located within the clip) to a parallelcondition (in which the anatomic tubular structure is constricted). Theplastic material is biodegradable.

Apart from the biodegradability of the plastic material, which limitsits utility to operations where only temporary occlusion or encirclingof a body passageway is required, the surgical articles of U.S. Pat. No.4,950,258 have a number of other disadvantages. The closing force is notparticularly strong, so that the shape memory induced closure of theclips is slow and unreliable. Moreover, the straight-legged clips areunworkable in a confined operating zone. Still further, no practicalapplicator device is disclosed.

Other shape memory materials are known, which have been tested for usein the surgical occlusion or encircling of body passageways.

WO-A 92/13490 (Friedland), for example, describes a surgical fasteningclip of a substantially U-shaped member of a shape memory metal alloy(eg Nitinol). The clip has an austenitic transformation temperature inthe range of 30 to 35°, i.e just below normal body temperature. A rangeof clip designs is illustrated. FIG. 4, for example, shows a clipgenerally having two straight legs joined to form the general U-shape.In FIGS. 15 and 16, the legs are each kinked into a zig-zag shape. InFIGS. 20 and 21 the low temperature shape is straight-legged, thezig-zag shape appearing only in the austenitic state. A general featureof the clips is that in the austenitic shape the legs are tightlyclamped together. The description teaches that the clips are to besqueezed down onto a vessel or tissue in the niartensitic (lowtemperature) state, whereupon heating to body temperature is allowed tooccur to change the alloy to its austenitic state and “lock” the clipinto the clamping condition (see, e.g. page 18, line 23 to page 19, line7).

The disclosure of WO-A-92/13490 does not fully answer the needs ofsurgeons. The closing force of the clips is too small to be usable as anactive occlusion and encircling system in a surgical procedure, i.e.where the clip itself closes onto a body passageway rather than beingsqueezed onto the body passageway by some external force. The need foran external force inherently limits the applicability of the prior artclips to surgical procedures where a clamping device can gain access tothe operating zone. In any event, the disclosure does not clearly teachan applicator device whereby the clips can be located in place in a realsurgical procedure and the transition from the martensitic to theaustenitic states controlled in the body temperature environment of anoperating zone within a patient's body.

U.S. Pat. No. 5,601,572 (Middleman et al), the disclosure of which isincorporated herein by reference, describes a surgical use ofpseudoelastic shape memory alloys in which the memorised physicaldeformation takes place without additional squeezing or other pressure,and is an essential feature of the operation of a surgical instrument.“Pseudoelasticity” is a behaviour exhibited by shape memory alloys in astress-induced martensitic condition. The instruments disclosed includea variety of devices in which generally an elongate member formed of ashape memory alloy is housed under stress within a hollow shaft of theinstrument and extended from/retracted into a distal end of the shaft atan operating zone within a patient. In its extended condition theelongate member adopts its “memorised” shape, to perform a variety ofsurgical tasks.

In FIGS. 1-4 to 1-12 of U.S. Pat. No. 5,601,572, for example, and in thedescription accompanying those figures, a surgical instrument isillustrated and described, in which an elongate pseudoelastic shapememory alloy member is used to secure a ligature about a blood vessel,by extending the member from, and retracting it into, the hollow shaftof the instrument. The procedure is slow and complex, as well as beingdifficult to control in a confined operating zone.

WO-A 98/58591 (Boston Scientific Corporation; filed Jun. 17, 1998;published Dec. 30, 1998), the disclosure of which is incorporated hereinby reference, describes a haemostatic clip formed of a materialexhibiting pseudoelastic behaviour at body temperature. Such materialsinclude shape memory alloys when in a stress-induced martensiticcondition, and this reference describes the use of generally U-shapedstaple-like haemostatic clips of such alloys which are individually heldunder stress with the legs of the clip forced into parallel alignment,at body temperature in an applicator device described as a “hypotube”(See FIGS. 1 to 5 and associated description). Upon release from thehypotube onto a blood vessel, the legs of the clip close together as theaustenitic phase predominates and the memorised shape is adopted. Acorresponding circular clip is illustrated in FIGS. 8 to 11, the clipbeing initially held confined in a curved hypodermic needle tostress-induce the martensitic condition. The closure of the clip istriggered by release of the stress, with no change in temperature.

The clips and applicators disclosed in WO-A-98/58591 suffer from anumber of disadvantages. A prime difficulty is that a relatively complexapplicator ejection system is required, because of the need to maintainthe stored clip under stress before discharge.

This makes the applicator unwieldy, the release operation difficult forthe surgeon, and limits the extent to which multiple clips can be loadedinto the applicator for repeated use during a surgical procedure.

Therefore, no effective and secure method for occluding or encirclingbody passageways has been available hitherto which satisfies therequirements of (a) being usable on a wide range of body passagewaysfrom small blood vessels to large ducts, (b) being quick and easy toexecute in all procedures, including open, micro and endoscopicprocedures, and (c) being at least as reliable as the conventionalmethods.

The present invention aims to go at least some way towards meeting theserequirements, or at least to provide an effective alternative to theknown methods.

SUMMARY OF THE INVENTION

The invention is based on the finding that a clip, comprising anelongate element having first and second ends and being resilientlymovable under an inherent biassing force between a first configurationin which the ends are spaced apart to allow a body passageway to passtherebetween and a second configuration in which the elongate element isdeformed, preferably generally helically wound, on itself so that theclip grips or encircles the body passageway, can be released or offeredtowards the body passageway in the first configuration using a clipdispensing apparatus, whereupon the clip resiliently deforms itselfaround the body passageway to encircle and optionally constrict andocclude the same. The expressions “helical” and “generally helicallywound”, used herein, refer to at least one end of the clip bendinginwardly around the body passageway, preferably to a condition where theends are overlapping or crossing one another at least to some extent,and in particular are not to be considered as limited only to circularor cylindrical configurations

Temperature-responsive shape memory materials, e.g. Nitinol alloys(nickel-titanium), are preferably to be used for this purpose. Thepreferred form of the present invention differs, however, from the priorart in that the transformation on which the shape memory is based is orincludes the temperature-induced martensitic to austenitictransformation, as opposed to only the pseudoelastic or stress-inducedmartensitic to austenitic transformation. In particular, the clip isheld in the dispensing apparatus at a temperature substantially belowbody temperature, and it is the body temperature of the operating zonethat triggers closure of the clip. In addition, a novel clip shape ispreferably employed, yielding substantial benefits in occlusionefficiency, and a novel applicator is also provided, in which preferablythe thermal characteristics, for example conductivity, of the operatingmechanism of the applicator itself contributes positively to thefunctioning of the clip.

The various features of the invention are as set forth in the claimsappended hereto, allowing for any principles of interpretation of thoseclaims as prescribed by law.

DETAILED DESCRIPTION OF THE INVENTION

Thus, in a first aspect of the present invention, there is provided asurgical apparatus for occluding or encircling a body passageway, theapparatus generally comprising:

(a) a housing holding one or a plurality of clips of the type describedabove in the first configuration thereof, the housing having a portthrough which an individual clip can be released to occlude or encirclethe body passageway;

(b) a drive member disposed within the housing and movable therein tourge a clip within the housing towards the port thereof, and

(c) a clip control device associated with the drive member and operableexternally of the housing to control the movement of the clip thereinand expulsion of the clip therefrom.

The clip control device is so arranged and/or the port of the apparatusis so configured that only one clip can pass through the port in any oneoperation of the clip control device.

Particularly when the apparatus is to be used in endoscopic surgery, thehousing suitably comprises a hollow shaft having a proximal end and adistal end, the port being provided at or near the distal end and ahandle being provided at or near the proximal end, in general proximityto the control device, whereby a surgeon can hold the apparatus.

It is preferred, although not essential, that the clips are held in aline within the hollow shaft of the housing and driven in that linetowards the open distal end. Alternatively, for example, they can beheld in a magazine and fed into the shaft one by one by clip feedingmeans. The clips are conveniently provided as a train of generally likeclips, all similarly oriented in the train. In some cases, the clips canconveniently be mutually frangibly connected to form a cartridge whichcan be loaded into the shaft or magazine. A guide member may suitably beprovided in the housing, which guide member supports the clip(s),slidably within the housing, in a location whereby the drive member canurge the clip(s) towards the port of the housing.

When referring to the elongate element of the clips for use in thedevice of the present invention, the expression “resilient” and likeexpressions used herein shall be taken to refer to all forms of inherentor internal (molecular) biassing of the elongate element of the cliptowards its second configuration. For example, a biocompatibletemperature-responsive “shape-memory” material can be used, in which theresilience is activated by a change (typically a rise) in temperature,so avoiding the need for the clip to be held in its first configurationagainst a restoring force. The “memorised” shape will be the second,e.g. helical, configuration. The “shape-memory” material may, forexample, be a metallic alloy such as Ti—Ni, Ni—Al, Ag—Cd or Au—Cd, anorbornene polymer, a nematic liquid crystal polymer, or an advancedthermoplastic elastomer such as a homopolymer of lactide or glycolide orcopolymers thereof. For further discussion of these materials, pleaserefer to U.S. Pat. Nos. 3,442,871, 3,797,499,3,839,297,4,505,767,4,523,591, 4,603,695 4,935,068 and 4,950,258, aswell as British Patent No. 1040168 (the disclosures of all of which areincorporated herein by reference), in addition to the prior artacknowledged above.

In summary, and as will be well known to those of ordinary skill in thisart, shape memory alloys are capable of transforming between martensiticand austenitic phases. This transformation between phases can be causedby a change in temperature. For example, a shape memory alloy in themartensitic phase will begin to transform to the austenitic phase whenits temperature rises above the austenite start temperature A_(s), andthe transformation will be complete when the temperature rises above theaustenite finish temperature A_(f). The transformation from austeniticto martensitic will begin when the temperature drops below themartensite start temperature M_(s), and will be complete when thetemperature drops below the martensite finish temperature M_(f). Thetemperatures M_(s), M_(f), A_(s) and A_(f) define the thermaltransformation hysteresis loop of the shape memory alloy, and can beadjusted with a relatively high degree of precision, in the case ofTi—Ni alloys by adjustment of the relative proportions of the nickel andtitanium.

The preferred material is a biocompatible and magnetic resonance imaging(MRI-) compatible temperature-dependent shape memory material having ashape transition temperature (martensite-to-austenite) in the range ofapproximately 20-35° C. This means that A_(f) should be no greater thanabout 35° and A_(s), should preferably be no less than about 20° C.,e.g. less than about 15° C. Such a material is Nitinol, which is anickel-titanium alloy comprising approximately 50 atomic percent nickel.For example, the alloy may be a binary alloy consisting of 50.8 atomicpercent nickel and 49.2 atomic percent titanium, or it may include aquantity of a third element such as copper, cobalt, vanadium, chromiumor iron. The binary alloy is preferred, as the more complex systemsgenerally have inferior biocompatability.

Alternatively, however, a temperature-dependent shape memory plastic ofthe types disclosed in the acknowledged prior art can be used.

Such clips should be stored in the martensite phase at a reducedtemperature (preferably below about 20° C., e.g. below about 15° C.), sothat, on deployment into the operating zone within the patient, thepatient's body temperature rapidly heats the clip to a temperature abovethe martensite-to-austenite shape transition temperature, preferablyabove A_(f). This has been found to impart a closing force of up to 200grams force onto the body passageway as the ends of the clip close tothe second configuration of the clip. In this way, the closing force canbe tailored to the intended end use of the clip, e.g. a crushing force(for haemostasis, for example) or a non-crushing force (for occludingbody ducts, e.g. in sterilisation).

At least the central portion of the clip, between the ends thereof, ispreferably formed of the resilient material. Preferably the whole clipis formed of the resilient material.

The said central portion of the elongate element of the clips istypically in the range of about 1 to 30 mm in length, depending on theintended use of the invention. The arrangement should preferably be suchthat in use the elongate element twists, e.g. helically, around a bodypassageway to match the size of the body passageway (encircling) or witha sufficient constrictive force thereon to occlude (at least partiallyclose) the body passageway. The selection of the precise material anddimensions of the elongate element for this purpose will be well withinthe capabilities of one of ordinary skill in this art.

The first and second ends of the clip preferably comprise legs extendingin the same general direction as each other from the intermediatecentral portion, the intermediate central portion being most preferablyconvoluted as will be described in more detail below. The term“generally the same direction” used herein refers to directions whichare broadly similar, i.e. less than about 120° separated, preferablyless than about 45° separated. This configuration will be referred toherein as a generally U-configuration.

The clips are very convenient for surgical placement, achievingpotentially up to about twice or three times the opening distance ofconventional surgical clips. It is most preferred that the ends of thelegs of the clip in the first configuration thereof should be spacedapart by no more than about 4 times the external diameter of the bodypassageway, more preferably no more than about 3 times the saiddiameter, and most preferably between about 1.5 and about 2.5 times thesaid diameter.

The legs of the clip in the first configuration thereof may be straightor curved, or may have straight and curved regions along their length.

The ends of the elongate element of the clip may conveniently besomewhat enlarged so that the clip in a fully straight configuration(which is not necessarily achievable in practice but may be onlytheoretical) would have the general appearance of a miniatureweightlifter's dumbbell. The surfaces of the ends of the elongateelement of the clip may be formed of a tough, low-friction,high-abrasion-resistance material such as, for example, ultrahighmolecular weight polyethylene. The ends of the clip can slide over eachother, optionally with a cam action, as the clip deforms into its second(helical) configuration. The folded-over ends of the clip are thussecurely fastened in the second configuration to encircle or constrictthe body passageway.

The elongate element of the clip between its ends may, for example, beof generally cylindrical, rectangular, triangular or squarecross-section.

In a particularly preferred form, the tightness of the helical windingis such that the diameter of curvature is less than about 2 mm. It ispreferred that the elongate element should not close on itselfcompletely, as this would carry a risk of severing the body passageway.The extent of closure will be readily selectable according to thedimensions and materials of the clip, and this is well within theabilities of one or ordinary skill in this art.

The clips may be permanent in the sense of non-absorbable by thepatient's body, or biodegradable (absorbable) within the patient's body.

In their first configuration, the clips may, for example, be alignedlongitudinally (end-to-end) or transversely (side-by-side). Where thefirst configuration of the clips is a generally U-configuration, theclips may be in chevron alignment nested together.

The preferred clip shape will now be described in more detail.

In the first (low temperature) configuration, the clip may suitably bein the general form of a staple, and preferably has a convoluted, e.g. azig-zag or sinuously curved, central portion, formed preferably ofNitinol wire, e.g. of substantially circular cross section. For a cliphaving legs approximately 2 mm apart in the first configuration theNitinol wire may suitably have a cross-sectional diameter ofapproximately 0.3 mm, and correspondingly larger or smaller clips willuse correspondingly thicker or thinner wire. The convoluted centralportion has at least one, preferably two, three or more, apices directedtowards the legs of the clip. These apices provide shoulders againstwhich the legs in the second (body temperature) configuration can urgethe body passageway.

The convoluted central portion has the further desirable property thatit permits the central portion of the clip to expand sideways slightlyin the second configuration (e.g. by a flattening of the sinuous curves)so allowing the legs to clasp towards the central portion of the clipwith a good angular presentation and therefore good mechanicaladvantage.

The legs of the clip are preferably integral with the central portionand consist of the same Nitinol wire, extending in generally the samedirection as each other in the first configuration of the clip and lyingpreferably in substantially the same plane as the convolutions of thecentral portion. In the first configuration of the clip, the legspreferably turn slightly mutually inwards and at their ends they arepreferably each provided with a wedge surface with suitably terminatesto a wedge apex line at the end of the respective leg. This wedge apexline may suitably be approximately parallel with the corresponding wedgeapex line of the opposing leg of the clip.

A little way along each leg from the terminal wedge surf ace there maysuitably be provided an enlarged inwardly directed nip-head projection,which may for example be rounded. This nip-head projection is arrangedto bear towards one of the inwardly directed apices of the convolutedcentral portion of the clip in the second configuration of the clip, tomaximise the pinching effect of the closure of the legs towards thecentral portion as the clip moves into the said second configuration.

In moving towards the second configuration of the clip, the convolutions(e.g. the zig-zag or sinuous curve) of the central portion of the clipmay straighten somewhat, accompanied by a slight reduction in theamplitude of the zig-zag or sinuous curves (e.g. by about 0.1 to about 2percent) and the legs close towards each other so that the wedgesurfaces slide over one another. For this purpose, the wedge apex linesmay suitably be slightly offset from one another out of the plane of theclip in the first configuration, so that they will not meet each otherprecisely square-on during the closing movement. In addition, theclosing movement involves the ends of the legs moving towards thecentral portion, so that the nip-head projection of each leg urges thebody passageway towards an inwardly directed apex of the convolutedcentral portion. This movement of the ends of the legs inwards towardsthe central portion may suitably have the effect of reducing theexternal dimensions of the clip (back of the central portion to front ofthe legs) by approximately 10 to 80%. Where the body portion has azig-zag or sinuous curve, the percentage reduction in the dimension ofthe clip may be towards the lower end of the range, e.g. about 10 t o30%, as the amplitude of the zig-zag or sinuous curve may itselfconstitute up to about 40 to 50% of the dimension, and this amplitudetypically changes only marginally as the convolutions of the centralportion straighten slightly, as described above.

As will be well known to those skilled in the art, the clips of thepresent invention will suitably be first formed in their second(austenite) configuration, e.g. by cutting and press-forming the Nitinolwire and bending the resulting form to shape, and the temperature isthen lowered to below the austenite-to-martensite transition temperature(i.e. to below M_(f)). The alloy atomic structure changes to the weakermartensite form, and the material can easily be deformed to a new shape,namely the first configuration.

Martensitic transformation comes about not through nucleation and growth(as in most crystal structure transformation of metals and alloys).Instead, it occurs through a much faster collective shear process, Thetransformation of interest in the present invention is thetemperature-induced martensitic transformation. The alternative possiblestress-induced or mechanical martensite transformation, and thepseudoelasticity and superelasticity that it produces, is notnecessarily a requirement of the present invention.

It is an important preferred feature of the apparatus that the distalclip, prior to expulsion from the apparatus, is held in the port of thehousing in its first (open) configuration, adjacent to the bodypassageway to be occluded or encircled and in such a way that the endsof the clip are free to deform onto the body passageway without externalpressure to close the clip. Once the closing movement has sufficientlyadvanced, the apparatus can be withdrawn, without any internally drivenpropulsion of the clip from the housing. The expression “expulsion” or“expelled” used herein to describe the dispensing of the distal clipfrom the apparatus, includes all forms of release, including passivedispensing in this sense, i.e. the withdrawal of the apparatus from theoperating zone so as to leave the clip in place on the body passageway.

The housing of the apparatus holds and supports one or more, preferablya plurality, of the clips in the first configuration thereof. Theplurality of clips may be in a line with the clips alignedlongitudinally (end-to-end) or transversely (side-by-side).Alternatively, a plurality of generally U-configuration clips may be ina chevron-like line. An even number of clips may suitably be used,particularly for procedures where body passageways need to be occludedat two points along their length. This prevents accidental exhaustion ofthe supply of clips during the procedure.

Certain clips in the first and/or second configurations thereof arenovel, irrespective of whether the material from which the clip isconstructed is a temperature-responsive shape memory material or anyother resilient material such as, for example, a conventional elastomer.These clips constitute further features of the present invention, andwhile their presentation to a body passageway may be accompanied by arise in temperature as the clip warms to the temperature of theoperating zone, this temperature rise is not an essential pre-requisitefor the closing of such clips into the second configuration thereof.

Thus, according to a further aspect of the invention, there is provideda surgical clip for occluding or encircling a body passageway, the clipcomprising an elongate element having first and second ends and anintermediate central portion, the clip comprising a resilient materialand being resiliently movable under an inherent biassing force from afirst configuration, in which the ends are spaced apart to allow thebody passageway to pass therebetween, to a second configuration in whichthe clip is deformed, preferably generally helically wound, on itself sothat the clip grips or encircles the body passageway, wherein:

(a) the first and second ends of the clip are legs which in the secondconfiguration of the clip are turned inwardly toward the intermediatecentral portion of the clip, whereby the body passageway is grippedbetween the legs and the intermediate central portion of the clip, orencircled by the legs and the central portion of the clip, theintermediate central portion being convoluted in at least the saidsecond configuration;

(b) the first and second ends of the clip are adapted, for exampleenlarged, so that in moving from the first to the second configurationthe ends of the clip can slide over each other, optionally with a camaction, as the clip deforms into its second configuration;

(c) the first and second ends of the clip are legs which are providedwith enlarged nip-head projections along their lengths, whereby in thesecond configuration of the clip the projections nip the body passagewayagainst the intermediate central portion of the clip;

(d) the first configuration of the clip is substantially rectilinear andthe second configuration of the clip is preferably generally helicallywound on itself, whereby if the clip comprises an elastomeric material,the first configuration is achievable by holding the clip constrained inthe said rectilinear configuration against a resilient restoring forcetending to move the clip into the second configuration thereof; or

(e) any combination of (a) to (d) above.

The housing preferably comprises a thermally insulating hollow shaftcontaining the clips and the drive member, the port being an open distalend of the shaft. In this preferred form of the invention, the covermember for the port is preferably a thermally insulating cup or thimblearrangement which can be manually removed for use, and replaced when theapparatus is not in use. This cover member is desirable so thattemperature-responsive clips in the housing do not warm up prematurely.

Alternatively, the cover member may be moved into and out of position byuse of a cover member control device operable externally of the housing.In a preferred form of such an arrangement, the clip control device andthe cover member control device are synchronised and actuable by asingle action of the surgeon. In such an arrangement, the cover memberfor the port of the housing preferably takes the form of a retractableshutter, movable back and forth in response to actuation of the covermember control device. The shutter preferably has a closed portion whichserves to cover the port of the housing when the closed portion and portare correspondingly aligned and an open portion which serves to uncoverthe port when the open portion and port are correspondingly aligned. Byproviding a retractable cover member at the port of the housing, and bysynchronising the clip control device and cover member control device sothat the drive member of the apparatus can only operate on the clipswhen the port is covered, there is no possibility of causing more thanone clip to become available to be released through the port in on“firing” (i.e. actuation) by the surgeon.

In a preferred form of the invention, therefore, the apparatus furthercomprises:

(d) a cover member for the port of the housing, the cover member beingmovable selectively to cover or uncover said port; and optionally

(e) a cover member control device operable externally of the housing tocontrol the movement of the cover member and thereby the expulsion ofthe clip from the housing.

The apparatus preferably includes a temperature control device formaintaining the clip(s) at the first temperature within the housing. Thetemperature control device may include a thermostat, for automatic finecontrol of temperature within the housing. Suitable temperature controldevices include electronic semiconductor-based cooling devices which usethe Peltier effect, or gas-expansion-based cooling devices which use theJoule-Thompson effect. The parts of the clip drive and control meanswhich support and contact the clips may suitably be thermoconductive(e.g. metallic), and in thermal contact with the temperature controldevice, whereby the temperature of the clips themselves can beeffectively controlled.

The drive member for urging a clip within the housing towards the portthereof suitably comprises a push member (e.g. a pressor rod) disposedat least partially upstream of the clips to be slidable within thehousing to urge against the line of clips within the housing. The pushmember is preferably spring biassed. The distal clip preferably lies inan expulsion station adjacent the port, from which it can be releasedfrom the apparatus either by its own inherent tendency to twist out ofits holding alignment or by an expulsion element provided in theapparatus. For example, an expulsion element may be required to breakany frangible connections in a cartridge of clips. The line of clips ispreferably oriented about its axis in such a way that the ends of thedistal clip will tend to move (twist) away from the port of theapparatus and around any adjacent body passageway.

The clip control device of the apparatus are preferably manuallyoperable by the surgeon (e.g. by finger pressure on a button ortrigger). The control of clip movement and expulsion is of greatimportance to the success of the apparatus, as the consequences ofincorrect “firing” of the apparatus would be catastrophic for a patient.

The clip control device of the apparatus preferably comprises a ratchetor cam device associated with the push member and operably linked to theremainder of the clip control device. In one preferred form, a springforwardly biasses the push member, the spring being releasable fromcontact with the push member, and the ratchet or cam device serves ineach actuation of the clip control device to take the spring out ofcontact with the push member when the port is open, thereby removing anyspring-loaded forward pressure on the clips while the port is open. Inanother preferred form, a spring rearwardly biasses the push member, andthe ratchet or cam device serves in each actuation of the clip controldevice to urge the push member in the forward direction (against therestoring force of the spring), which again serves to locate the distalclip in the port of the housing without any forward pressure on theclips while the port is open.

When the housing comprises a shaft, e.g. in the case of a device for usein endoscopic surgery, the port of the shaft may, for example, bepresent at its distal end face or a side port may be provided in thewall of the shaft near its distal end. In the first form, the shaft canbe pushed onto a body passageway before a clip is expelled onto the bodypassageway. However, in this configuration the surgeon's endoscopic viewof the body passageway may be obscured by the shaft of the apparatus ofthe present invention. In the second form, which may avoid thisdisadvantage, the apparatus may be brought alongside the body passagewaybefore the apparatus is actuated.

The apparatus may be constructed from any convenient materials. Metalssuch as, for example, stainless steel may be used. Plastic polymers suchas, for example, ultrahigh molecular weight polyethylene or polyacetylmay be used. Of course, different materials may be used for differentparts. Metal is preferred for the internal mechanism, with plasticpreferred for the outer housing.

As mentioned above, the apparatus may conveniently be provided with aproximal handle whereby the surgeon can hold the apparatus. The clipcontrol device and, if present, cover control device are preferablyactuable via a single finger trigger or button associated with thehandle. The ergonomically configured handles and finger-control systemsdescribed in WO-97/42884 are particularly suitable, and the disclosureof that earlier publication is incorporated herein by reference.

Moreover, when used in endoscopic surgery, the device may convenientlybe used with the improved instrument support systems for endoscopicsurgery described in WO-97/42884.

The apparatus may suitably be provided in disposable and reusable parts,which are releasably connectable together for use. The “disposable”part(s) is/are suitably provided in sterile individual packs, and the“reusable” part(s) is/are suitably provided in sterilisable materialsand in an sterilisable configuration.

The disposable part(s) may suitably include the clips, and may forexample comprise at least a major portion of the shaft of the housing inthe preferred apparatus form. The clips may be pre-loaded in the shaft,so that all that is necessary for the surgeon or his or her assistant todo is to connect the disposable shaft to the reusable handle part.Alternatively, the disposable part may comprise a magazine or cartridgeof clips, which is loaded into reusable apparatus.

Where it is convenient, and where suitable laboratory or workshopfacilities are available the “disposable” part(s) may in fact be maderecyclable, e.g. reloadable With clips, resettable into theready-for-use configuration, and resterilisable.

One particular surgical method for occluding or encircling a bodypassageway, enabled by the apparatus of the present invention, generallycomprises:

(a) providing a clip comprising an elongate element having first andsecond ends and an intermediate central portion, the clip comprising atemperature dependent shape memory material and being resilientlymovable, in response to an increase in temperature from a firsttemperature, substantially below body temperature, to body temperature,under an inherent biassing force from a first configuration, in whichthe ends are spaced apart to allow the body passageway to passtherebetween, to a second configuration in which the clip is deformed onitself so that the clip grips or encircles the body passageway, the clipbeing provided at the first temperature and in the first configurationthereof;

(b) offering the clip to the body passageway so that the body passagewayis received substantially between the ends of the clip; and

(c) allowing the temperature of the clip to rise to approach bodytemperature by the proximity of the body passageway to the clip, wherebythe clip deforms into its second configuration around the bodypassageway.

In another aspect, the surgical method for occluding or encircling abody passageway, using the apparatus of the present invention, generallycomprises:

(a) locating the surgical apparatus such that the port of the housing isin proximity to the body passageway;

(b) operating the clip control device to cause a clip to be expelledfrom the port of the housing of the apparatus, whereby upon release inits first configuration from the apparatus the clip resiliently deformsitself onto the body passageway to occlude or encircle the bodypassageway; and

(c) removing the apparatus from proximity to the body passageway.

BRIEF DESCRIPTION OF THE DRAWINGS

For ease of understanding the present invention, embodiments will now bedescribed, without limitation and purely by way of example, withreference to the accompanying drawings, in which:

FIG. 1 shows in partial vertical cross-section a surgical apparatus foroccluding or encircling a body passageway;

FIG. 2 shows in artificially-transparent detail a clip used in theapparatus of FIG. 1, in its first (straight) configuration;

FIG. 3 shows the clip of FIG. 2 in its second (helical) configuration;

FIG. 4 shows the process of occlusion of a body passageway by the clipafter expulsion from the device of FIG. 1;

FIG. 5 shows schematically in transverse cross-section on the line V—Vof FIG. 1 the synchronisation of the closure and clip drive means of theapparatus of FIG. 1;

FIG. 6 shows an enlarged vertical cross-section of part of the apparatusof FIG. 1, showing part of the clip drive means in more detail;

FIG. 7 shows an enlarged cross-sectional view along the line VII—VII ofFIG. 6, looking in the direction of the arrows;

FIG. 8 shows an enlarged cross-sectional view along the line VIII—VIIIof FIG. 6, looking in the direction of the arrows;

FIGS. 9 and 10 show the part of FIG. 6 at different stages of thetrigger actuation and release cycle;

FIG. 11 shows the outward design appearance of the apparatus of FIG. 1with the trigger in the resting condition and the port closed;

FIG. 12 shows a perspective external view of an alternative surgicalapparatus for occluding or encircling a body passageway, with a firstdesign of distal end cover;

FIG. 13 shows in perspective view the apparatus of FIG. 12 with thedistal end cover removed;

FIG. 14 shows a detail of the distal end of the apparatus of FIG. 12,with a partial cut away view of clips within the shaft, the distal endcover being to a second design;

FIG. 15a shows a perspective detail of an alternative distal end coverfor use with the apparatus of FIGS. 12 to 14;

FIG. 15b shows a vertical cross-sectional view of the distal end coverof FIG. 15a;

FIG. 16 shows a vertical longitudinal cross-sectional view of theapparatus of FIG. 12, showing the separation of the handle and housingparts;

FIG. 17 shows a schematic perspective view of the proximal end of thehousing part of the apparatus of FIGS. 12 to 16, to illustrate the drivemember and clip control device;

FIG. 18 shows a vertical cross-sectional view of the apparatus of FIG.16, along the line XVIII—XVIII and looking in the direction of thearrows;

FIG. 19 shows the clip present in the apparatus of FIGS. 12 to 18, (a)in its first (low temperature) configuration and (b) in its second (bodytemperature) configuration;

FIG. 20 shows the two configurations (a) and (b) from FIG. 19 inoverlain relationship, to illustrate the deformation changes that theclip undergoes, and showing in the small insert box details of thecross-sectional configurations at various points; and

FIG. 21 shows a side view of the clip of FIG. 19(a), looking from theleft.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring firstly to FIGS. 1 to 11 of the drawings, a surgical apparatusfor occluding or encircling a body passageway 1 (e.g. a vein or artery)during endoscopic surgery comprises a housing in the general form of ahollow shaft 2 holding a line of surgical clips 3. The apparatus will bedescribed herein only with reference to at least partial occlusion ofthe body passageway. Encirclement of a body passageway withoutconstriction can be achieved by selecting the appropriate tightness ofwinding of the helical configuration of the clip. The shaft 2 has aproximal end 4 and a distal end 5. The distal end 5 of the shaft 2 isprovided with a port 6 through which an individual clip 3 can bereleased. The port 6 is openable and closable by means of a cover member7 for the port, the cover member 7 being movable selectively to cover oruncover the port by means of cover member control means operableexternally of the housing to control the movement of the cover member.The cover member control means will be described in more detail below.

In the apparatus of FIGS. 1 to 11 there is no internal temperaturecontrol device. This apparatus is suitable for use in a relatively coolambient environment, or in conjunction with a cool holster in which theapparatus is held when not in use.

Drive means comprising a releasably spring-biassed pressor rod 8 aredisposed within the shaft 2 and are slidable along the inner space ofthe shaft to urge the line of clips 3 within the shaft towards the port6. The spring biassing, when applied in the resting condition, urges thepressor rod 8 towards the line of clips (to the night as viewed in FIG.1), as will be described in more detail below. The pressor rod 8 thussenses to position the distal clip of the line at an ejection station atthe distal end of the shaft 2, from which, using the inherent tendencyof the clip to twist, it can be released through the open port 6 of theshaft. The line of clips is orientated about its axis in such a way thatthe ends of the distal clip will tend to twist out of the apparatus andaround any adjacent body passageway 1. It should be noted that the clipis not actively pushed out of the apparatus; it curls around the bodypassageway in response to the temperature rise in the operating zoneadjacent the body passageway, and the apparatus can then be withdrawn toleave the clip in place.

The apparatus includes clip control means which comprise means forcontrolling the said movement of the pressor rod within the shaft. Theseclip control means are synchronised with the cover member control means.More particularly, and as will be described in greater detail below, thespring biassing is released from the pressor rod 8 whenever the port 6is open, thereby removing any urging force on the line of clips 3, toprevent multiple expulsion of clips. In this way, the movement of theclips in the shaft 2 and their individual expulsion from the port 6 ofthe shaft 2 can be controlled from the proximal end of the device by thesurgeon. The control means are operable externally of the apparatus viaa finger-actuable trigger button 9 mounted on an ergonomicallyconfigured handle 10 for the apparatus. The handle 10 is provided withsurface depressions 11, 12 whereby a surgeon can grip the handle fastbetween thumb and middle finger, and is sufficiently short that thesurgeon can freely move the palm of his or her hand over and around theend of the handle without releasing the grip on the handle.

The line of clips 3 will now be described in detail. In the embodimentshown, each clip of the line is discrete from its neighbour, although afrangibly-connected line of clips can alternatively be envisaged. Eachclip 3 comprises a central elongate element 13 having somewhat enlargedfirst and second ends 14, giving it the general appearance of aminiature weightlifter's dumbell.

The clip may be formed of a “shape-memory” biocompatible polymer,preferably by moulding, and if necessary the ends 14 may be providedwith a coating of ultrahigh molecular weight polyethylene, although“memory” metal may, for example, alternatively be used. This provides alow-friction surface when the enlarged ends slide over one another in acam action as the clip closes around the body passageway 1.

The “memorised” shape of the clip is a tightly wound helix or spiral, asshown in FIGS. 3 and 4, and the material of the clip is such that theclip moves rapidly into that configuration in response to thetemperature rise which is associated with release from the apparatusinto an operating zone within a patient's body. The inner diameter ofthe spiral can be predetermined by adjusting the length of the elongateelement 13. In addition, the torsional force applied to the bodypassageway 1 can be altered by adjusting the thickness of the elongateelement 13 and by altering the physical state of the material at thetime of initial deformation. These modifications are routine for thoseof ordinary skill in the art of resilient (e.g. “shape memory”)materials.

Alternatively, the clips may be formed of an elastomeric material whichis stored in a stretched form in the apparatus, and reverts to apre-formed generally helical resting condition upon release from theapparatus, under the influence of the elastic restoring force.

FIG. 4 shows the stages in the application of a haemostatic clip 3across a body passageway (in this case a vein). In Stage I the openhaemostatic clip 3 is positioned across the vein. Upon release from theapparatus the haemostatic clip 3 begins to move to its generally helicalshape (Stage II), In Stage III the haemostatic clip 3 wraps around thevein, occluding the lumen.

The clip is stored in a straight configuration within the shaft 2 of theapparatus (FIG. 1), and is urged along, the shaft in that configuration.

Referring now particularly to FIGS. 1 and 5 to 10, the apparatus will bedescribed in more detail. The apparatus comprises three main sections;the handle 10, with trigger mechanism; a main body 14, having a casingwall and containing as clip control means a proximal ratchet releasesystem 15 for the spring biassing the pressor rod 8, and a sprung cammechanism 16 for opening and closing the port 6; and lastly the shaft 2,which comprises an outer shaft 2 a, an inner hollow shaft 2 b providingthe cover member control means (the inner shaft 2 b being proximallyconnected to the sprung cam 16 of the body 14), and the central pressorrod 8.

The handle 10 is of the pencil type, as described generally inWO-97/42884, with a mid-point third finger—thumb pivot, and provisionfor both second and fourth finger control on the forward (right asillustrated) surface 18. On the section adjacent to the body 14 of theapparatus lies the trigger 9. This is depressed for release of ahaemostatic clip 3 by opening of the port 6, whereby the end clip twistsout of the shaft 2, with simultaneous release of the pressor effect ofthe central pressor rod 8. One haemostatic clip 3 is released when thetrigger 9 is fully depressed and the mechanism then remains static untilrelease of the trigger by the surgeon, whereupon the inner hollow shaft2 b rotates to a 90° opposed position, so closing the distal port 6.Trigger release also causes the spring biassing to be reapplied on thepressor rod 8, thereby causing the pressor rod 8 to move forward andresume its forward effect upon the remaining haemostatic clips 3 in theapparatus.

The body 14 houses the links from the trigger 9 to the ratchet releasesystem 15 and the cam mechanism 16. The cam mechanism 16 comprises alightweight face-plate or cam 19, having a central aperture whichreceives the inner shaft 2 b whereby the cam 19 is fixedly mounted onthe inner shaft 2 b. The cam is sprung via two opposed wire springs 20,21, attached to the body casing 22. A link rod 23 from the trigger 9 isattached to one corner 19 a of the cam, and rotates the cam 90° back andforth. Owing to the lightweight nature of the cam and inner shaft andthe balance spring effect, the whole mechanism flips back and forth uponrespective actuation and release of the trigger 9.

The link rod 23 moves up and down in line with the long axis of thehandle 10. Behind the trigger 9 within the handle there is a slidinghinged mechanism 23 a with yokes 23 b to restrain the link rod 23 in thehorizontal direction, which translates the reciprocal horizontal actionof the trigger into the reciprocal vertical up and down movement of thelink rod 23. The trigger is sprung (not shown) and thereby has a naturaltendency to resume the extended, non-depressed state upon release by thesurgeon.

In the embodiment shown, the shaft 2 is permanently closed over itsdistal end face 24 and fashioned from lightweight material, which isbiologically inert, such as stainless steel. The outer 2a and inner 2bshafts are each provided with a side opening near the distal endthereof, forming the port 6 of the shaft. The opening of the outer shaft2 a is generally in line with the handle 10, i.e. on the under side ofthe shaft of the apparatus as illustrated in FIG. 1. The inner shaft 2 bis rotatable within the outer shaft, as previously described, and thearrangement is such that the opening of the inner shaft can be alignedwith the opening of the outer shaft to open the port 6 formed by thealigned openings. When the inner shaft 2 b is rotated to the release, or‘open’ position (FIG. 5) the two openings lie coincidental, providing anunhindered release for a haemostatic clip 3 through the port 6.

FIG. 5 shows a functional schematic diagram of this process. It showsthe ‘opening’ process upon actuation of the trigger by a surgeon'sfinger 25 and the ‘closing’ process upon release of the trigger 9. Thesestates (“open” and “closed”) refer to the condition of the port 6. Withfinger pressure (arrow A) the trigger 9 moves to the left as illustrated(is depressed), the two arms of the hinged mechanism move closertogether within the handle 10 and thereby force the sliding mechanismdown, away from the body 14 of the apparatus, so pulling the link rod 23down, further along the handle 10. This rotates the cam 19 around, andthereby rotates the inner shaft 2 b, this rotation being against therestoring force of the opposed wire springs 20, 21. The cam 19 is squarein shape and rotates, sliding as it does so against the inner wall ofthe body casing, which is suitably of plastic. Once it begins to rotateit assumes an unstable position and can either flip back to the stablerest position (if the surgeon inadvertently, or purposefully prematurelyreleases the trigger before completion of the cycle). With continuedfinger pressure on the trigger, however, the cam 19 springs around tothe next stable position (full length side of the cam 19 against theinner casing wall), which is reached with full depression of the trigger9. At this point the inner shaft has moved through 90°, and the twodistal openings lie coincidental. The port 6 is thus open and a clip canbe released by its inherent tendency to twist out of the shaft.

Upon release of the finger pressure on the trigger 9, the hinged armsmove apart, the link rod 23 moves up and the cam 19 rotates in thereverse direction. The sprung cam 19 moves around until it reaches theoriginal stable position, the port 6 closes and the trigger 9 moves backto the neutral position.

The mechanism for temporary release of the spring biassing the pressorrod 8, in synchrony with the opening of the port 6, will now bedescribed with particular reference to FIGS. 1 and 6 to 10.

FIG. 6 shows a median partial longitudinal section of the proximalratchet mechanism, housed within the body 14 casing. This mechanismcontrols the releasable spring biassing of the pressor rod 8 insynchrony with the opening and closing of the port 6. The mechanismcomprises three main parts: a fixed hollow central casing part 26, whichis mounted to the body 14 casing; a slidable part 27 which moves to andfro relative to the central casing part 26; and a ratchet part 28 withinthe central casing part 26.

The slidable part 27 is operatively linked to the trigger 9 by means oftracker rods 29, 30, 31 (see also FIG. 1) which transfer the horizontalmovement of the trigger directly into horizontal movement of theslidable part 27. Trigger springs (not shown) are associated with thetracker rods 30,31, which urge the trigger and thereby the slidable part27 into the resting (non-depressed) condition as shown in FIG. 1. Theslidable part 27 is limited in its movement with respect to the centralcasing part 26 by stops 32.

The ratchet part 28 includes: a central ratchet rod 33 slidably mountedcoaxially upon a central ratchet rod guide pin 33 a which extends fromthe slidable part 27 along a significant portion of the length of theratchet rod, internally of the ratchet rod 33; circumferential ratchetteeth 34 provided at intervals along the ratchet rod 33 in such a numberand spacing that the ratchet mechanism will engage and function atgenerally the beginning of each trigger depression action; a pair ofopposed releasable longitudinal ratchet gears 39 disposed over theratchet rod 33 and having concave terminal teeth 39 a which can overliethe circumference of the ratchet rod 33 and engage with the teeth 34 ofthe ratchet rod 33 when the ratchet gears are brought into engagementwith the ratchet rod 33; a pair of transverse supports 37 extendingacross the central space of the casing part 26 on opposed sides of theratchet rod 33 and each serving to support the respective ratchet gear39 in an outwardly resiliently biassed manner by means of anintermediate arched leaf spring 37 a mounted to the transverse supportand further to slidingly guide the respective ratchet gear in itstransverse to and fro movement into and out of engagement with theratchet rod 33 via cooperating guide channels 37 b of the transversesupports 37 and lateral projections 39 b of the ratchet gears; (theguide channels 37 b of each transverse support 37 being in the form ofmutually inwardly directed vertical slots along each of which therespective lateral projection 39 b of the ratchet gear can slide to andfro—i.e. towards and away from the ratchet rod correspondingly to themovement of the ratchet gear—and the lateral projections 39 b beingsmaller than the width of the guide channels 37 b so that pivotalmovement of the ratchet gears is possible via the sliding pivotarrangement provided by each guide channel 37 b and lateral projection39 b, while nevertheless the ratchet gear 39 is held captive by theguide channels 37 b as far as longitudinal movement (i.e. to left orright as viewed in FIG. 6; respectively into or out of the paper asviewed in FIG. 8) is concerned); a pair of elongate resiliently bendableratchet adjusters 35 mounted to the slidable part 27 and extendingtherefrom to overlie the ratchet gears 39 and each having a terminalT-head 36 providing one terminal projection 36 a extending away from therespective ratchet gear and one terminal projection 36 b extendingtowards the respective ratchet gear; and a pair of angled shoulders 26 bprovided on the interior wall of the casing 26 which cause aconstriction between the casing wall and each ratchet gear 39 wherebythe angled shoulder 26 b of the casing wall can cooperate in a camaction with the projection 36a of each ratchet adjuster 36 when theratchet adjuster 36 is drawn into the region of constriction (to theleft as illustrated; see Arrows X in FIG. 9) in response to depressionof the trigger, to force the ratchet gear into engagement with theratchet rod, against the restoring force of the leaf springs 37 a.

An advance spring 40 is held under compression and overlies the ratchetrod 33 between the distal end 33 a of the ratchet rod 33, to which thedistal end 40 a of the spring is mounted, and a shoulder 26 a of thecasing part, against which the proximal end 40 b of the spring bears.The restoring force of the advance spring thus urges the pressor rod 8forward (to the right as illustrated; see Arrows Y in FIG. 10) when theratchet and pressor rods are in contact.

Depression of the trigger 9 causes the slidable part 27 to move to theleft as illustrated, relative to the central casing part 26, as far asthe stops 32. This pulls the heads 36 of the ratchet adjusters 35 overthe portions of the ratchet gears 39 which rest on the leaf springs 37a. The heads 36 are forced onto the ratchet gears by the constriction inthe casing, against the restoring force of the leaf springs 37 a. Thisforces the ratchet gears 39 to grip against the ratchet rod 33. Theteeth 34 of the ratchet rod soon engage with the teeth 39 a of theratchet gears. Continued depression of the trigger 9 causes the slidablepart 27 to pull the ratchet rod 33 to the left, to the point of fulldepression of the trigger (FIG. 9).

At the same time as the ratchet rod 33 is pulled to the left inassociation with the slidable part 27, the advance spring 40 iscompressed. The pulling of the ratchet rod 33 out of contact with thepressor rod 8 releases the pressor effect on the haemostatic clips 3. Atfull depression of the trigger 9 a distal haemostatic clip is releasedfrom the apparatus, by the synchronised opening of the port 6. Theremaining haemostatic clips 3 lie passively in line within the innershaft 2 b.

Upon release of the trigger 9, the port 6 closes and the trigger springsback to its resting condition. The slidable part 27 moves back (to theright) relative to the central casing part 26, and the heads 36 of theratchet adjusters 35 move (to the right) out of the region ofconstriction of the casing wall (FIG. 10). Resilience of the ratchetadjusters 35 causes them to resume a parallel resting configuration outof contact with the ratchet gears 39. The pressure on the ratchet gears39 is thus released and the ratchet gears 39 in turn lift off thecentral ratchet rod 33, under the restoring force of the leaf springs 37a. In turn, the ratchet adjusters 35 are splayed out of the way by thesame restoring force (FIG. 10). The ratchet rod 33, being spring loadedby the advance spring 40, is thus released, rapidly advances forwardwithin the inner shaft 2 b, thereby re-exerting the pressor effect uponthe haemostatic clips via the pressor rod 8. The line of clips thenmoves forward to take up the space vacated by the released clip, and theapplicator is ready for the next application.

Referring now generally to FIGS. 12 to 21, an alternative surgicalapparatus for occluding or encircling a body passageway comprises ahousing in the general form of a hollow shaft 2′ holding a line ofsurgical clips 3′. This alternative apparatus is designed for use in arelatively warm operating theatre environment.

The shaft 2′ has a proximal end 4′ and a distal end 5′. The distal end5′ of the shaft 2′ is provided with a port 6′ through which anindividual clip 3′ can be released. The port 6′ is openable andcloseable by means of a cover member 7′ for the port, the cover member7′ being movable selectively to cover or uncover the port by manualoperation. The cover member 7′ takes the general form of a thermallyinsulated cup or thimble which can be manually push-fitted onto thedistal end 5′ of the shaft 2′ to cover the port 6′, and manually removedby a reverse procedure to uncover the port 6′. The cover member 7′ mayhave external projections 7 a′, to enable the surgeon or his or herassistant to achieve a better grip on the cover member. The cover member7′ may suitably be formed of an insulating plastic such as ultra highdensity polyethylene or polyacetyl. The cup or thimble has two plasticlayers, 7 b′, 7 c′, preferably further provided with a closely fittinginner liner 7 d′, also of plastic.

A drive member comprising a releasably spring-biassed pair of holdingrails 8′ of arcuate cross-section and in fixed mutual relationship aredisposed within the shaft 2′ and are slidable along the inner space ofthe shaft to urge the line of clips 3′ held in contact with the rails8′, within the shaft to urge the line of clips 3′ within the shafttowards the port 6′. The spring biassing is achieved by means of areturn spring 8 a′ provided between the rails 8′ and the proximal end 4′of the shaft 2′, as shown in detail in FIG. 17. The return spring 8 a′bears at one end against a pair of opposed spacer members 8 b′, fixed tothe inner wall surface of the shaft 2′ and adapted to space the internalparts from the wall of the shaft 2′, and at the other end against a pairof spring stops 8 c′ which project radially outwards from the holdingrails 8′ (only one spring stop 8 c′ shown, in FIG. 17).

The apparatus includes a clip control device which controls the movementof the clips and the drive member within the shaft. More particularly,and as will be described in greater detail below, the clips 3′ in theshaft are spaced apart via stops in the form of rounded projections on acentral stator member, which is stationary with respect to longitudinalmovement within the shaft but is transversely movable to and fro withinthe shaft under a spring bias. An orthogonal double synchronised camdevice, spring loaded and actuable by external thumb or finger pressurefrom the surgeon, simultaneously retracts the stator member out of theplane of the line of clips so that the rounded stops do not impedeadvancement of the line of clips, advances the line of clips oneclip-worth by urging of the holding rails 8′ forward within the shaft 2′towards the distal end 5′ 9 of the shaft, then restores the statormember back towards the plane of the line of clips so that the roundedstops impede reversal of the line of clips, and finally actuates theeffect of the return spring 8 a′ on the holding rails 8′ so that itmoves back to its resting position in the shaft, sliding over the lineof retained clips as it does so.

In this way, the movement of the clips in the shaft 2′ and theirindividual expulsion from the port 6′ of the shaft 2′ can be controlledfrom the proximal end of the device by the surgeon. The clip controldevice is operable externally of the apparatus via a finger actuabletrigger button 9′ mounted on an ergonomically configured handle 10′ forthe apparatus. The handle 10′ is provided with surface depressions 11′,12′ whereby a surgeon can grip the handle.

As shown particularly in FIG. 16, the proximal end of the drive memberand clip control device is housed within a hollow, generally conical,proximal part 50 of the housing, which is separable from the handle 10′.It is preferred that the housing, including the shaft 2′, the generallyconical proximal part 50, the internal mechanisms and parts and theloaded clips 3′, will be supplied as a separate sterile unit which canbe simply fitted (e.g. screwed or push-fitted) onto the reusable handlepart. The sterile unit is not necessarily thrown away when the clipshave been used, however. It may be taken apart, reloaded with clips andresterilised if desire, although this would have to be done in aworkshop environment.

The clip control device will now be described in more detail, withparticular reference to FIGS. 16 to 18.

The thumb-actuable button 9′ is disposed at one end of a spindle rod 51provided within the proximal housing part 50, the spindle rod beingmounted at its other end to a compression spring 52 which spring biassesthe button 9 and spindle rod 51 to the resting condition.

Generally centrally along the length of the spindle rod 51 there isprovided the orthogonal double cam arrangement comprising a cone surface53 scalloped on its underside (as viewed in FIGS. 16 and 17, FIG. 16being considered as a top view and FIG. 17 being considered as aperspective view more from the side).

The cone surface 53 bears against the proximal end of the pair ofholding rails 8′ as the button 9′ is depressed, urging the rails 8′ intothe shaft 2′. Because the rails 8′ are holding the clips 3′ between them(see FIG. 18), this will move the clips in the shaft 2′ towards thedistal port. Full depression of the button 9′ will move the rails 8′ andclips 3′ by one clip increment, so introducing the distal clip 3′ intothe distal port 6′ of the shaft.

The clips 3′ are held in mutually spaced apart relation within the shaftby means of a stator member 54, which is located between the rails 8′.The stator member is stationary with respect to longitudinal movementwithin the shaft but is transversely movable to and fro within theshaft, as shown by the double-headed arrow in FIG. 18, under thebiassing effect of spring 52. The stator member carries a series ofspaced stops 55 along its length, the stops comprising roundedprojections spaced one clip separation apart.

Extending from the proximal end of the stator member to its underside isa crooked finger projection 56 having an appropriately angled tip, whichslides over the underside of the cone surface 53 as the cone surfacemoves when the button 9′ is depressed. This secondary cam action causesthe stator member 54 to retract from the plane of the clips sufficientlythat the line of clips can be advanced in the shaft 2′ by the primarycam action on the pair of rails 8′ and the clips 3′. However, as soon asthe scallop indentation 57 in the underside of the cone surface 53 isreached, the retraction of the stator member 54 stops.

On release of the button 9′, springs 8 a′ and 52 release and act toreturn the mechanism to its resting condition. However, thesynchronisation is such that the stops 55 of the stator member 54 moveinto the plane of the line of clips before that line of clips has beenmoved back by the rails 8′. Therefore, the stator member 54 catches theclips in their advanced state, and prevents them from moving backtowards the proximal end of the shaft. Instead, the rails 8′ merelyslide back over the clips.

It is a feature of this apparatus that the clips are held in the shaft2′ at a relatively constant depressed temperature. This is achieved byproviding a temperature control device in the handle 10′. Thetemperature control device serves to maintain the temperature of theparts of the shaft within the range of about 5 to 20° C., even when theinstrument is being held by a surgeon or assistant, or is being used ina hot environment.

The temperature control device as illustrated is a Peltier effectthermal pump. The Peltier effect is a known cooling effect and Peltiereffect heat pumps are marketed, e.g. by RS Components, P.O. Box 99,Corby, Northamptonshire, UK (telephone:+44 1536 201234). Anyconventional Peltier device with a sufficient cooling effect can beused. In general terms, the Peltier effect, which was discovered in 1834by Jean Peltier, relies on the phenomenon that the passage of anelectric current through the junction of two dissimilar conductors caneither heat or cool that junction, depending on the direction of thecurrent. Heat generation/absorption rates are proportional to themagnitude of the current and the temperature of the junction. Incommercial devices, semiconductors doped both p and n type typicallyform the elements of the couple and are soldered to copper connectingstrips. Ceramic faceplates electrically insulate these connecting stripsfrom external surfaces. A suitable semiconductor material is bismuthtelluride.

Alternatively (not illustrated) a gas cooling device may be used,whereby the cooling effect of expansion of a pressurised gas (e.g.carbon dioxide) can be used to provide the necessary cooling, using theJoule-Thompson effect.

Thermostatic control (not shown) of the internal temperature of theapparatus may be provided, whereby the temperature can be maintained ata desired level.

In all cases, however, it is preferred that the cooling device be housedcompletely within the handle.

The cooling device is therefore a Peltier effect heat pump 58 whichcools on its forward surface 59 (directed towards the interior of thehousing) and pumps any heat gained towards the opposing surface 60. Thissurface 60 is in thermal contact with a metal heat sink 61, allowing theheat to be conducted away and lost to the atmosphere via a vent 62 inthe end cover 63 of the handle. The end cover 63 is conveniently adaptedas an on-off rotatable switch to acuate the cooling device, the vent 62being open in the “on” position as shown in FIG. 16. A high currentbattery 64 is also contained Within the handle, and the outer casing ofthe handle is suitable made thermally and electrically insulating. Thebattery 64 is connected to a conventional electronic circuit board 65provided with electrical components which reduce the relatively highvoltage from the battery and provide a suitable current. A lightemitting diode (LED) 66, indicates when the device is “on”.

The internal mechanism of the housing is suitable formed predominantlyof metal, for example stainless steel. In this way, the cooling effectof the heat pump in the handle is transferred efficiently to the clips.To maintain the apparatus as cool as possible, the terminal cover member7′ should be applied to the distal end of the shaft 2′ whenever theapparatus is not in use. This prevents warm air from contacting thedistal end clip of the apparatus. Alternatively or additionally, theshaft of the apparatus can be kept in an insulated or cooled holsterwhen the apparatus is not in use.

The shaft itself and the proximal housing part 50 may most convenientlybe made of a synthetic plastic such as ultrahigh molecular weightpolyethylene or polyacetyl. This material is also convenient for thehandle casing, since it provides excellent thermal/electrical insulationand structural durability. It is also suitable biologically, and has anon-slip surface.

The shaft 2′ is designed to afford maximum external thermal insulationto the clips until final release. The distal end 5′ is therefore shapedto afford the surgeon the convenience of pre-positioning the U-shapedmouth 6′ across a vessel or duct, before trigger release. Triggerrelease does not propel the clip out of the end, but rather simply movesit into the U shaped terminal mouth 6′ of the shaft, where it can bewarmed by the anatomical structure. The clip is not mechanicallydeformed by the action of the trigger. This enables the releasemechanism to be a simple light-touch button and not a conventionaltrigger shaped to provide mechanical leverage, which is traditionallynecessary to crush and deform conventional clips.

Should a surgeon accidentally misplace a clip, a cooled probe can beapplied to the clip to return the clip to its first (open)configuration, after which it can be removed and a fresh clip reappliedusing the apparatus. Alternatively, the clip can be snipped or cut, sothat it will fall away from the body passageway.

The apparatus may be provided with a clip counting device or anindicator device, to alert the surgeon when the supply of clips isbecoming exhausted. A simple indicator would, for example, be atransparent window towards the distal end of the shaft, whereby thesurgeon or his or her assistant can see when the supply of clips isabout to be exhausted.

Referring particularly to FIGS. 19 to 21, the preferred clipconstruction will now be described in detail.

In the first (low temperature) configuration the clip 3′ is in thegeneral form of a staple, having a convoluted central portion 70 in theform of a sinuous curve. The clip is formed of circular cross sectionNitinol wire.

The central portion 70 has two legs 71, 72 extending therefrom ingenerally the same direction.

The convolutions of the central portion provide two apices 73, 74directed towards the legs 71, 72 respectively. These apices provideshoulders against which the closing force of the legs in the second(body temperature) configuration can urge the body passageway.

As shown in FIG. 20, for example, the convoluted central portion of theclip has the desirable property that it permits the central portion ofthe clip to flatten at least the outer curves in the secondconfiguration (see FIG. 20), so allowing the legs 71, 72 to claspinwards towards the central portion of the clip with a good angularpresentation and therefore good mechanical advantage. This deformationis illustrated by conside ring the changes to angles α and β as shown inFIG. 19, as the clip moves from its first (a) to its second (b)configuration. As shown in FIG. 19, angle α closes from about 59° toabout 57°, whereas angle β opens from about 13° to about 53°.

The legs turn slightly mutually inwards and at their tips they are eachprovided with a wedge surface 75 which terminates to a wedge apex 76 atthe end of the respective leg.

A little way along each leg 71, 72 there is provided an inwardlydirected nip-head projection 77, of generally somewhat rounded profile(see the profiles in FIG. 20). This nip-head projection is arranged tobear towards one of the inwardly directed apices 73, 74 of theconvoluted central portion of the clip in the second configuration ofthe clip, to maximise the pinching effect of the closure of the legstowards the central portion in the said second configuration.

It is preferred that in the second configuration of the clip (see FIG.19(b)) the ends of the legs overlap. The degree of overlap shown in FIG.19(b), for example, is sufficient to constitute “generally helicalwinding” within the terms of this patent. In achieving this overlap, thewedge surfaces 75 slide across each other. For this purpose, the wedgeapices 76 are slightly offset from one another in the firstconfiguration of the clip (see FIG. 21), so that they will not meet eachother precisely square-on during the closing movement.

In addition, as shown in FIGS. 19 and 20, the closing movement involvesthe ends of the legs moving towards the central portion, so that eachnip head projection 77 of each leg urges the body passageway (not shown)towards a respective one of the inwardly directed apices 73, 74 of thecentral portion.

The end result is secure and highly effective constriction or encirclingof the body passageway between the legs of the clip and the centralportion.

The foregoing broadly describes the invention without limitation toparticular embodiments thereof. Variations and modifications as will bereadily apparent to those of ordinary skill in this art are intended tobe included within the scope of this application and subsequentpatent(s).

What is claimed is:
 1. A surgical apparatus for occluding or encirclinga body passageway, the apparatus comprising: (a) a housing holding atleast one clip, wherein the at least one clip comprises an elongateelement having first and second ends and an intermediate centralportion, the at least one clip comprising a temperature-dependent shapememory material and is resiliently movable, wherein in response to atemperature increase from a first temperature to a second temperature,the at least one clip changes under an inherent biassing force from afirst configuration in which the first and second ends of the at leastone clip are spaced apart to allow the body passageway to passtherebetween, to a second configuration in which the at least one clipis deformed on itself so that the at least one clip grips or encirclesthe body passageway, wherein the at least one clip is held at the firsttemperature within the housing in the first configuration, wherein thehousing has a port through which at least one clip can be released toocclude or encircle the body passageway; (b) a drive member disposedwithin the housing and movable therein to urge at least one clip withinthe housing towards the port thereof; and (c) a clip control deviceassociated with the drive member and operable externally of the housingto control the movement of the at least one clip therein and expulsionof the at least one clip therefrom.
 2. The apparatus of claim 1, furthercomprising: a cover member for the port of the housing, wherein thecover member is movable selectively to cover or uncover the port.
 3. Theapparatus of claim 1, further comprising: a temperature control devicefor maintaining the at least one clip at the first temperature withinthe housing.
 4. The apparatus of claim 3, wherein the first temperatureis from about 0° C. to about 25° C.
 5. The apparatus of claim 4, whereinthe first temperature is from about 5° C. to about 10° C.
 6. Theapparatus of claim 1, wherein the second temperature is about 37° C. 7.The apparatus of claim 1, wherein each of the at least one clip isaligned in the housing with the ends directed generally towards the portof the housing.
 8. The apparatus of claim 7, wherein each of the atleast one clip is connected together in a cartridge arrangement.
 9. Theapparatus of claim 1, wherein the at least one clip is held undersubstantially zero mechanical stress.
 10. The apparatus of claim 1,further comprising: a guide member which slidably supports the at leastone clip in a location whereby the drive member can urge the at leastone clip towards the port of the housing.
 11. The apparatus of claim 1,wherein the port of the housing is adapted to lie adjacent to the bodypassageway externally and to receive a clip internally, whereby the endsof the clip substantially overlie the body passageway and are free tomove in response to heat transferred to the clip from the bodypassageway and any surrounding body tissues and fluids, the movement ofthe ends of the clip being a movement closing the clip around the bodypassageway.
 12. The apparatus of claim 1, wherein the port of thehousing is configured as a notch at a distal end of a hollow shaft, thenotch being adapted to receive the body passageway externally and theclip internally.
 13. The apparatus of claim 1, wherein the portion ofthe apparatus that is in contact with the at least one clips comprises athermoconductive material, whereby body heat is conveyed to at least oneclip immediately prior to expulsion thereof and is conveyed away from aremaining at least one clip when the apparatus is not in use.
 14. Theapparatus of claim 1, wherein the at least one clip is adapted so thatin the second configuration thereof the at least one clip is generallyhelically wound on itself around the body passageway.
 15. A surgicalclip for occluding or encircling a body passageway, the clip comprisingan elongate element having first and second ends and an intermediatecentral portion, the clip comprising a temperature-dependent shapememory material and being resiliently movable, wherein in response to atemperature increase from a first temperature to a second temperature,the clip changes under an inherent biassing force from a firstconfiguration in which the first and second ends of the clip are spacedapart to allow the body passageway to pass, therebetween, to a secondconfiguration in which the clip is deformed on itself so that the clipgrips or encircles the body passageway, wherein the first and secondends of the clip are legs which in the first configuration of the clipextend in the same general direction as each other from the intermediatecentral portion, wherein the intermediate central portion has at leastone apex directed generally towards the legs of the clip.
 16. Thesurgical clip of claim 15, wherein the clip comprises a shape memoryalloy.
 17. The surgical clip of claim 16, wherein the alloy is Nitinolhaving an austenite finish temperature A_(f) no greater than about 35°C.
 18. The surgical clip of claim 17, wherein the Nitinol has anmartensite start temperature M_(s) which is at least 10° C. below A_(f).19. The surgical clip of claim 15, wherein the intermediate centralportion of the clip has a zig-zag shape.
 20. The surgical clip of claim15, wherein the intermediate central portion of the clip has a sinuouslycurved shape.
 21. The surgical clip of claim 15, wherein theintermediate central portion of the clip has at least two apicesdirected generally towards the legs of the clip.
 22. The surgical clipof claim 15, wherein the legs of the clip are provided at their endswith mutually inwardly directed wedge surfaces, whereby the ends canslide over each other on closure of the clip.
 23. The surgical clip ofclaim 15, wherein each leg of the clip is provided with an enlargednip-head projection, inwardly directed relative to an apex of thecentral portion of the clip and arranged to bear towards the apex onclosure of the clip.
 24. The surgical clip of claim 15, wherein thefirst and second ends of the clip are legs which in the secondconfiguration of the clip are turned inwardly toward the intermediatecentral portion of the clip, whereby the body passageway is grippedbetween the legs and the intermediate central portion of the clip, orencircled by the legs and the central portion of the clip, theintermediate central portion being convoluted in the secondconfiguration.
 25. The surgical clip of claim 15, wherein the first andsecond ends of the clip are adapted so that in moving from the first tothe second configuration, the ends of the clip can slide over each otheras the clip deforms into its second configuration.
 26. The surgical clipof claim 15, wherein the first and second ends of the clip are legswhich are provided with enlarged nip-head projections along theirlengths, whereby in the second configuration of the clip, theprojections nip the body passageway against the intermediate centralportion of the clip.
 27. The surgical clip of claim 15, wherein thefirst configuration of the clip is substantially rectilinear and thesecond configuration of the clip is generally helically wound on itself,whereby if the clip comprises an elastomeric material, the firstconfiguration is achievable by holding the clip constrained in saidrectilinear configuration against a resilient restoring force tending tomove the clip into the second configuration thereof.
 28. The surgicalclip of claim 15, being of a dimension suitable for use in haemostasis.29. The surgical clip of claim 15, being of a dimension suitable for usein ligation.
 30. The surgical clip of claim 15, being of a dimensionsuitable for use in male or female sterilisation.
 31. The surgical clipof claim 15, being of a dimension suitable for use in vascularocclusion.
 32. The surgical clip of claim 15, being of a dimensionsuitable for use in cardiac occlusion.
 33. The surgical clip of claim15, being of a dimension suitable for use in the occlusion of body ductsprior to resection.
 34. A surgical method for occluding or encircling abody passageway, comprising the steps of: (a) providing a clipcomprising an elongate element having first and second ends and anintermediate central portion, the clip comprising a temperaturedependent shape memory material and being resiliently movable, inresponse to an increase in temperature from a first temperature,substantially below body temperature, to body temperature under aninherent biassing force from first configuration, in which the ends arespaced apart to allow the body passageway to pass therebetween, to asecond configuration in which the clip is deformed on itself so that theclip grips or encircles the body passageway, wherein the first andsecond ends are legs which in the first configuration extend in the samegeneral direction as each other from the intermediate central portion,and the intermediate central portion has at least one apex directedgenerally towards the legs of the clip, the clip being provided at thefirst temperature and in the first configuration thereof; (b) offeringthe clip to the body passageway so that the body passageway is receivedsubstantially between the ends of the clip; and (c) allowing thetemperature of the clip to rise to approach body temperature by theproximity of the body passageway to the clip, whereby the clip deformsinto its second configuration around the body passageway.
 35. Thesurgical method of claim 34, including the steps of: (a) utilizing asurgical apparatus having a housing for holding the clip, the housinghaving a port through which a clip can be released; and (b) offering theclip to the body passageway by locating the port of the surgicalapparatus in proximity to the body passageway and expelling a clipthrough the port, whereby the clip resiliently deforms itself onto thebody passageway.